Retractable specimen holder for a microtome

ABSTRACT

A microtome in which the feed is accomplished by a screwadjusted nose cam against which is biased an inclined plane. The inclined plane is a part of the specimen head which reciprocates relative to the microtome knife. The nose cam is screw advanced at the top of each stroke before the next downward or cutting stroke. A The nose cam is eccentrically and rotatably mounted relative to the microtome frame. At the bottom of each cutting stroke, this nose cam is rotated causing it to displace laterally, allowing the inclined plane and the specimen head to retract slightly from the knife for the upstroke.

United States Patent [72] inventor Norman W. Shatzel Williamsville, N.Y. [21] Appl. No. 5,708 [22] Filed Jan. 26, 1970 [45] Patented Dec. 21, 1971 [73] Assignee American Optical Corporation Southbridge, Mass.

[54] RETRACTABLE SPECIMEN HOLDER FOR A MICROTOME 2 Claims, 3 Drawing Figs.

[52] US. Cl 83/414, 83/9155 [51] Int.Cl G0ln 1/06 [50] Field of Search 83/411, 412, 414, 915.5

[56] References Cited UNITED STATES PATENTS 3,293,972 12/1966 Burkhardt 83/9155 X 1,026,280 5/1912 Ott 83/9155 X 3,077,806 2/1963 Hellstr0m..... 83/412 X 3,299,758 1/1967 McCulloch... 83/9155 X 3,487,739 1/1970 Murphy etal. 83/9155 X Primary Examiner-Wil1iam S. Lawson Attorneys-William C. Nealon, Noble S. Williams and Robert .1. Bird ABSTRACT: A microtome in which the feed is accomplished by a screw-adjusted nose cam against which is biased an inclined plane. The inclined plane is a part of the specimen head which reciprocates relative to the microtome knife. The nose cam is screw advanced at the top of each stroke before the next downward or cutting stroke.

The nose cam is eccentrically and rotatably mounted relative to the microtome frame. At the bottom of each cutting stroke, this nose cam is rotated causing it to displace laterally, allowing the inclined plane and the specimen head to retract slightly from the knife for the upstroke.

INVENTOR.

ATTORNEY NORMAN W. SHATZEL BOTTOMWTOP PATENTEU um! m E: EEEE FIG. 2

RETRACTABLE SPECIMEN HOLDER FOR A MICROTOME BACKGROUND OF THE INVENTION The present invention is related generally to microtomes and in particular to the feed mechanism by which a microtome specimen is advanced relative to the knife for successive cutting strokes.

In the prior art, typically, a microtome specimen head or holder reciprocates relative to a stationary knife blade. The advance for successive cuts is made at the end of the return stroke so that the next cutting stroke effects the cutting of another layer from the specimen. On the return stroke, the specimen rubs against the back of the knife blade. It is desirable to avoid this by retracting the specimen a small amount to clear the knife on the return stroke to avoid compression of the specimen for the next cut.

It is an object of the present invention to provide a microtome feed mechanism which will permit the retraction of the sample relative to the knife blade for its return stroke.

Other objects, advantages and features of the present invention will become apparent from the following description of one embodiment thereof when taken in connection with the accompanying drawing.

DRAWING FIG. 1 is a plan view representing, somewhat schematically, certain elements of a microtome apparatus;

FIG. 2 is a partial side view of the apparatus taken along line II-II in FIG. 1; and

FIG. 3 is a view taken substantially along line IIIIII of FIG. 1.

DESCRIPTION Referring now to FIG. 1, part of a microtome is generally indicated at 2 and includes a frame, schematically represented at 4, and a movable specimen head or holder generally indicated at 6. Specimen head 6 includes a specimen clamp located at 8 and inclined planar bearing member 10. Specimen head 6 is movable up and down (into and out of the plane of the drawing) relative to frame 4 on ways indicated at 12. Similarly, specimen head 6 is movable relative to frame 4 horizontally in the direction indicated by arrow 14 along ways indicated at 16.

Specimen head 6 is spring biased against a nose cam 18. Cam 18 is fixed to a cam chuck 20. Cam chuck 20 is, in turn, rotatably mounted relative to a carriage member 22. Carriage 22 is mounted so as to be movable relative to frame 4 as indicated by arrow 24. The horizontal movement of carriage 22 relative to frame 4 is effected by an adjusting screw mechanism, shown somewhat schematically at 26.

The following conventions will be used to define relative movements:

X-Axistranslation of specimen head 6 (arrow 14).

Y-Axistranslation of carriage 22 (arrow 24).

Z-Axis-reciprocation of specimen head 6 (arrow 36).

As is known, when specimen head 6 reciprocates in the Z- axis relative to frame 4, feed adjusting screw 26 moves nose cam 18 along the Y-axis in the direction of arrow 24 so as to move the specimen head 6 incrementally along the X-axis in the direction of feed shown by arrow 14. When the specimen head 8 is at the top of its stroke, the feed screw 26 is moved to effect this incremental feed adjustment prior to the next downward or cutting stroke of the specimen head.

Referring now to FIG. 2, the inclined plane surface 10] includes a flange 28 and a flange 30 extending horizontally from its upper and lower ends respectively. Cam chuck 20 includes a pair of adjustable pins 32 and 34 fixed thereto, and extending respectively upwardly and downwardly therefrom. These pins are displaced from the axis of carn chuck 20 as shown in FIGS. 1 and 3. As specimen head 6 reciprocates along the Z- axis indicated by arrow 36, at the bottom of the stroke, pin 32 contacts flange 28 at the top of the stroke, pin 34 contacts flange 30. The contacting of flange 28 and pin 32 causes a small angular rotation of cam chuck 20 at the bottom of the stroke. Similarly, the contact of flange 30 and pin 34 causes a small angular rotation of chuck 20, in the opposite direction, at the top of the stroke.

Referring now to FIG. 3, an arrow 38 indicates the small angular displacement through which chuck 20 moves by the coaction of pins 32 and 34 and flanges 28 and 30. Nose cam 18 is eccentrically mounted relative to cam chuck 20. Thus, when chuck 20 is angularly displaced at the ends of the specimen stroke, nose cam 18 is laterally displaced a small amount relative to the inclined plane surface 10. That is, at the top of the stroke specimen head 6, flange 30 acting through pin 34 cause nose cam 18 to swing slightly to the right as shown in FIG. 3. This causes the advancing of the specimen head 6 into cutting position. At the bottom of the stroke, flange 28 acting through pin 32 causes nose cam I8 to swing slightly to the left as shown in FIG. 3. This permits the specimen head 6 to retreat slightly relative to the microtome knife blade for the upstroke. Thus, on the upstroke the specimen does not rub against the blade.

This cyclical retraction and resetting of the specimen relative to the knife is independent of the intermittent actuation of feed screw 26, which takes place in the normal and known manner at the top of each stroke. Thus, it will be apparent that a microtome apparatus has been provided in which the specimen is permitted to travel clear of the knife on its return stroke.

It may occur to others of ordinary skill in the art to make modifications of the present invention which will lie within its concept and scope and not constitute a departure therefrom. I Accordingly, it is intended that the invention be not limited by i the details of its description but only by the following claims.

I claim:

1. A microtome apparatus in which a specimen holder advances relative to a stationary knife blade along an X-axis and reciprocates relative to said knife blade along a Z-axis, said specimen holder being integral with an inclined planar bearing surface, said surface being biased against a carriage-mounted nose cam, which advances along a Y-axis to effect the translation of said specimen holder along said X-axis, said apparatus being characterized by the following improvement:

said nose cam being eccentrically and rotatably mounted relative to its carriage,

means to angularly displace said nose cam relative to said carriage in a first direction at the top of the stroke of said specimen holder and in a second opposite direction at the bottom of the stroke of said specimen holder,

the angular displacement of said :nose cam effecting its lateral displacement relative to said bearing surface.

2. A microtome apparatus as defined in claim I, the improvement further including cooperating abutment elements on said specimen holder and said eccentrically mounted nose cam to effect said angular displacement.

IOIOIS 0170 

1. A microtome apparatus in which a specimen holder advances relative to a stationary knife blade along an X-axis and reciprocates relative to said knife blade along a Z-axis, said specimen holder being integral with an inclined planar bearing surface, said surface being biased against a carriage-mounted nose cam, which advances along a Y-axis to effect the translation of said specimen holder along said X-axis, said apparatus being characterized by the following improvement: said nose cam being eccentrically and rotatably mounted relative to its carriage, means to angularly displace said nose cam relative to said carriage in a first direction at the top of the stroke of said specimen holder and in a second opposite direction at the bottom of the stroke of said specimen holder, the angular displacement of said nose cam effecting its lateral displacement relative to said bearing surface.
 2. A microtome apparatus as defined in claim 1, the improvement further including cooperating abutment elements on said specimen holder and said eccentrically mounted nose cam to effect said angular displacement. 